A R/N toucher works perfectly because this boss is a prot monk with very little healing capability.
Bring a full team of H/H, kill all the foes around Chaelse (equipping frozen soil on one of the heroes fastens this part), then send H/H outside radar and touch the boss to death.
I've H&Hed him NM. No point in trying to solo all the way there, just solo him. I've used a Moebius/Blossom assa, he doesn't stand a chance. Off to HM now...